The invention relates to an installation for coating food products with a fine pulverulent material, such as flour or breadcrumbs, comprising an endless conveyor belt which allows the pulverulent material to pass through and has a top part and a bottom part, means for forming a layer of pulverulent material on a portion of the top part on which the products can be accommodated and can be moved in the direction of transport, as well as means for applying a layer of pulverulent material on the products present on the top part, which means comprise a container having a discharge for the pulverulent material, as well as distribution means which allow the pulverulent material to pass through, for uniformly distributing the pulverulent material over the width of the top part.
An installation of this type is disclosed in U.S. Pat. No. 5,238,493. The pulverulent material is fed to the distribution means in a more or less thick layer, and at a certain speed, from a hopper located above the conveyor belt. Problems arise especially when feeding a relatively thin layer of pulverulent material at low speed, as is required in order to coat the products with relatively little pulverulent material. Under these conditions lumps of the pulverulent material form, which lumps drop onto the distribution means.
The known distribution means are found not to be readily capable of distributing the locally higher concentrations of pulverulent material issuing therefrom uniformly over the entire width of the conveyor belt. The quantity (volume) of pulverulent material dispensed is, moreover, not continuous over time. The result of this is that some products on the belt receive too much pulverulent material and other products too little.
The aim of the invention is to provide an installation of the type described above which does not have these disadvantages and makes better, more uniform distribution of the pulverulent material possible. Said aim is achieved in that the distribution means comprise a distribution element that is located transversely below the discharge and allows the pulverulent material to pass through, as well as a part, such as a plate, located below the distribution element, that does not allow the pulverulent material to pass through.
The pulverulent material that issues from the container does not fall directly through the distribution element onto the products but is initially impeded by the plate underneath. Because any lumps now first impinge on the plate, these are broken up. The pulverulent material can then not only be dispensed such that it is uniformly distributed but also continuously over time. With this arrangement the plate acts as a buffer.
To promote uniform dispensing, the distribution element and the plate can be oriented at a slight angle of inclination, sloping downwards towards the top part. The pulverulent material can slide off over the distribution element and the plate in a controlled manner, by which means the result can be further improved.
Preferably, the lowest, downward-sloping edge of the distribution element extends beyond the plate, such that the pulverulent material is able to drop through the distribution element beyond the plate. The distribution element is brought into back-and-forth vibration or a shaking movement transversely to the top part of the conveyor belt.
The distribution element can be constructed in various ways, for example as a sieve. However, the preference is for a circulating, endless shaking belt which runs around the plate, such that the plate is below the top part of the distribution belt.
Should some lumps still nevertheless remain, it must be possible for these to be removed in a reliable manner without their being able to get onto or between the products. To this end, a transverse guide can be present close to the lowest end of the distribution element, for removing lumps of pulverulent material to the side.
With this arrangement the residual pulverulent material can be dispensed because there is a passage between the transverse guide and the lowest edge of the plate, through which the pulverulent material is able to fall.
Preferably, the transverse guide is oriented sloping towards a discharge end for removal of the lumps. Furthermore, the transverse guide can be profiled on that side thereof which faces the plate, the profiling being asymmetric in such a way that the lumps are forced towards the discharge end under the influence of the shaking movement.